Several conventional igniter assemblies for gas turbines have been developed. FIG. 1 illustrates an example of such a conventional igniter assembly 110 used to control leakage of air flowing through an opening 118 within a combustion liner 119. As illustrated in FIG. 1, the conventional igniter assembly 110 provides an igniter boss 115 which extends from the perimeter of the opening 118 and encircles an igniter 114 to minimize an air flow into the igniter cavity and through the opening 118.
FIG. 2 illustrates another example of a conventional igniter assembly 210 to control leakage of air flowing through an opening 218 within a combustion liner 219. The conventional igniter assembly 210 provides an igniter 214 disposed within an igniter housing 216. An igniter boss 215 extends from the perimeter of the opening 218 to a base 226 of the igniter housing 216, to minimize the air flow into the igniter cavity and through the opening 218.
An additional example of a conventional igniter assembly is disclosed in U.S. Pat. No. 6,920,762 to Wells et al. As illustrated in FIG. 2 of Wells et al., an igniter assembly 38 provides an igniter 36 with a tip 44 that passes through an opening 47 in an outer casing 30, a pair of springs 42,52, a first ring 46 and an opening 40 in a combustion liner 16 adjacent to a combustion chamber 14. The igniter assembly 38 positions the igniter 36 between an outer casing 30 and the combustion liner 16 to maintain an alignment of the igniter 36 with respect to the combustion liner opening 40. Since the outer casing 30 has a greater thermal growth characteristic than the combustion liner 16, the outer casing 30 experiences thermal growth which exceeds that of the combustion liner 16. During such thermal growth, the outer casing 30 and igniter 36 slide in a radial direction relative to the combustion liner 16, and the springs 42,52 impart a predetermined load between the outer casing 30 and the liner 16 in order to maintain the alignment of the igniter 36 through the opening 40.